Refrigeration



Mai'ch 1945- s. w. E. ANDERSSON ,37 ,0

REFRIGERATION Filed Aug. 21, 1941 2 Sheeis-Sheet l INVENTOR I Q ATTORNEY-March 20, 1945.

s. w. ANDERSSON 2,372,044

REFRIGERATION Filed Aug. 21, 1941 2 Sheets-Sheet 2 I VENTOR 34w 2 M M@ATTORNEY Patented Mar. 20', 1945 I REFRIGERATION Sven W. E. Andersson,Evansville, Ind., assignor to Servel, Inc., of Delaware New York, N. Y.,a corporation Application August 21, 1941, Serial No. 407,746 8 Claims.(Cl. 62-5) My invention relates to refrigeration and has for its objectto provide an improvement in thermostatic control of refrigerationapparatus, as will appear from the following description taken inconjunction with the accompanying drawings forming a part of thisspecification, and of which:

Fig. 1 illustrates more or less diagrammatically refrigeration apparatusand a heating system therefor provided with a thermostatic controlembodying the invention;

Fig. 2 is a bottom view of the thermostatic control shown in Fig. 1;

Fig. 3 is a sectional Fig. 4;

Fig. 4 is a 'sectionalview taken at line 44 of Fig. 3; and

Fig. 5 is a sectional view taken at line 55 of Fig. 4.

The refrigeration apparatus shown is of a twopressure absorption typegenerally as described in application Serial No. 239,762 of A. R. Thomasand P. P. Anderson, Jr., filed November 10, 1938, now Patent No.2,282,503 granted May 12, 1942. A system of this type operates at lowpressures and includes a generator III, a condenser I I, an evaporatorI2, and an absorber I4 which are interconnected in such a manner thatthe pressure differential in the apparatus is maintained by liquidcolumns.

The generator includes an outer shell Within which are disposed aplurality of vertical riser tubes I6 having the lower ends thereofcommunicating with a spacelI and the upper ends thereof extending intoand above the bottom of a vessel Ill. The spac I9 within shell and Iabout the tubes I6 forms a steam chamber to which steam is suppliedthrough a conduit from a steam boiler 2| The boiler 2| is provided witha fire or heating tube 22 into the lower end of which is adapted toproject the flame produced by a burner 23. A combustible gas isdelivered to burner 23 from a source of supply through a conduit 24 inwhich is connected an electro-magnetically operated valve 23 connectedby conductors 28 and 21 to a suitable source of electrical energy.-While only a single heating tube and burner are illustrated. a numberof heating tubes and burners may be employed with the upper end of eachtube connected to a flue or riser 28. The water in boiler 2| is heatedby hot gases passing through the heating tubes 22, thereby producingsteam which flows through conduit 20' to generator Ill.

The space l9 provides for full length heating of riser tubes It with avent 30 provided at the upper view taken at line 3-3, of

end of shell l5 into the atmosphere. Condensate formed in steam chamber|9 is returned to boiler 2| through a conduit 3|, a condensate returnpump 32 and a conduit 33. The condensate return pump 32 is adapted to beoperated by an electric motor 32 mounted thereon, so that returncondensate can be raised to a higher level from which it can flow toboiler 2|.

The heating of riser tubes IS in generator ID by the steam causesrefrigerant vapor to be expelled from absorbent, such expelled vaporbeing eflfective to raise liquid absorbent by gas or vapor-lift action.The expelled vapor passes from the upper ends of the riser tubes intovessel l8, and thence flows through a conduit 34 into condenser H inwhich the expelled vapor is liquefied. The liquid refrigerant formed incondenser flows through a U-tube 35 into the upper part of evaporator|2. The refrigerant evaporates in evaporator |2 with consequentabsorption of heat to produce a refrigerating effect which may be utilized to cool an air stream such as, for example, the air caused to flowthrough a duct 36 which is indicated in dotted lines.

The refrigerant vapor formed in evaporator i2 ilows therefrom to anabsorber 4 in which the vapor is absorbed into a liquid absorbent, suchas lithium chloride solution, for example, which enters the upper partat the absorber through a conduit 31. The absorption liquid enriched inrefrigerant is conducted from absorber |4 through conduit 38, a firstpassage in liquid heat exchanger 39, conduit 40, vessel 4 I, and conduit42 into space ll of generator I0. Refrigerant vapor is expelled out ofsolution in generator I 0 by heating, and the solution is raised by gasor vapor-lift action in riser tubes l6, as explained refrigerant sincerefrigerant vapor has been expelled therefrom in generator I0. Theabsorption liquid in vessel |8 flows therefrom through conduit 43, asecond passage in liquid heat exchanger 39, and conduit 31 into theupper part of absorber 4. This circulation of absorption liquid resultsfrom theraising of liquid in riser tubes l6, whereby such liquid canflow to absorber I4 and return from the latter to the generator by forceof gravity. The upper part of vessel 4| and vessel It are connected by aconduit 43, so that thepressure inthe vessel is equalized with thepressure in the upper part of generator II and condenser ll.

f The absorber l4 and condenser ll constitute through whichsteam canflow 1 heat rejecting parts of the refrigeration apparatus and arecooled by a suitable cooling medium, such as water, for example, whichis conducted from a suitable source of supply through a conduit 44 to abank of tubes 45 within the absorber, whereby heat of absorption isgiven up to the cooling water. The cooling water is conducted fromabsorber |4.through a conduit 46 to condenser H in which heat ofcondensation is given up to the cooling water, the cooling water thenceleaving the condenser through a conduit 41,

In order to simplify the drawings the parts of the refrigerationapparatus have not been shown in detail, such an illustration of theparts not being necessary for an understandin of this invention. Thedisclosure in the-aforementioned Thoma and Anderson application may be'considered as being incorporated in this application and, if desired,reference may be made thereto for a detailed description of therefrigeration apparatus.

In accordance with my invention a. thermostatic of such clip beingadapted to press and slide over the top of switch 5| and at the sametime con-,

stantly press and urge blade 65 against the underside of guide member63. v

The blade 65 is'spring-biased to move toward the right in Figs. land 5.Thi is accomplished by a coil spring 61 having one end thereof securedto a leg or extension68 on blade 65 and the opposite end thereof securedto a pin 69 fixed toa side wall 51 of shell 54. When the portion ofblade 65 extending outside of shell 54 is pulled outward a sufficientdistance against the action of coil spring 61 a lip-or tongue 10, whichi pressed from one surface of the blade 65, is adapted to contact andengage an edge of guide member 63 to keep the spring clip 66 in thesolid line position shown in Fig. 4. Under these conditions switch 5| isnormally closed to complete the electrical circuit for valve 25.

When movement is imparted to a pin 1| at the top side of blade 6550 thatthe lip or tongueis free and clear of guide member 63, the

control device 50 is provided for controlling elec- 1 tro-magneticallyoperated valve and hence the flow of gas to burner 23. The thermostaticcontrol comprises a switch 5| which is connected in conductor 26. asshown in Fig. l. The switch 5! is of the normally closed type so that anelectrical circuit is normally completed for valve 25 through conductors26 and 21 for energizin the valve to keep the latter open. However, whenan adverse operating condition occurs, as will be excoil spring 61becomes effective. tomove the blade '65 toward the right in Figs. 4 and5 until the right hand end strikes an end wall- 56 'of shell 54. Withthe blade 65 in the position shown in Fig. 5, the spring clip 66 is inthe dotted line po- I sition in Fig. 4, so that'the flat outerend there-I of presses against the pin or plunger53 of switch I 5|. With thespring clip 66 acting againstthe pin 53 the switch contacts areseparated by snapaction movement, as explained above, and the plainedpresently, the contacts of switch 5| are separated to open theelectrical c rcuit for valve 25 whereby the latter closes to shut offflow of gas to burner 23.

The switch 5| is of a well known micro-switch type generally like thatdescribed in Patent No. 1,960,020 and having an exterior casing 52formed of. a suitable insulating material, such as Bakelite, forexample. The switch contacts within casing 52 are normally closed andare separated by a snap action when an inward movement of 45approximately .001 inch is imparted to a pin or plunger 53 which passesthrough an opening in the top of the casing, as shown most clearly inFigs. 3 and 4.

electrical circuit for valve 25 is broken.

Movement is imparted to pin 1| by mechanism including an expansiblefluid thermostat including a thermal element 12 of hollow constructionformed from a pair of diaphragms having the peripheral edge portionsthereof secured together in anysuitablemanner. The expansible fluidthermostat is charged with a suitable volatile fluid and, in addition tothe element 12, includes a pair of thermal bulbs 15 and 16 and acapillary tube 12' connecting the-bulbs and the element.

The element 12 i arranged to overlie the upper top of shell 54 withdiametrically opposite peripheral edge portions thereof contacting anden- The switch 5| is mounted in the bottom part of a rectangular-shapedshell having a bottom 55, end walls 56, side walls 51, and flanges 58and 59 extending outwardly from the top edges of the side walls 51. Toone of the side walls 51 is secured, as by welding, for example. a flatplate 51' which extends below the bottom and serves as a continuation ofthe side wall. 1 The switch 5| is secured in position by bolts 60 whichpass through openings in the plate 51 and the base of switch 52 and areadapted to receive tightening nuts 6|. The bottom 55 of the shell 54 isformed with an opening to receive the switch 5| so that the switch ispartly enclosed by the shell, as shown most clearly in Fig. 4. Thebottom of switch 5| is provided with terminal connections 62 adapted tobe connected to conductor 26, as explained above.

An inverted U-shapedguide member 63 is secured at 64 to the Side wall 51from which the flange 59 extends. The guide member 63 is arranged toreceive and hold a part hereinafter gaging the flanges 58 and 59. Theelement 12 is located on the flanges 58 and 59 so that the bottomdiaphragm with fiexure thereof is capable of acting on pin 1|. A ring 13is provided about the peripheral edge of element 12 and is arranged tobe clamped in position by a suitable bracket 14 having openings whicharein alignment with similar openings in flanges 58 and 59 and adapted toreceive bolts and tightening screws, a indicated at 15' in Figs. 2, 3,and 5, ior securing the bracket to the shell 54. The bracket 1-4 isformed so that pressure is only applied to clamping ring 13 to hold theelement 12 in position, the dome or rounded central portion Ofthebracket being spaced from the bellows, as clearly shown in Figs. 3 and4.

In the illustrated embodiment of the invention,

the expansible fluid thermostat serves as a single control devicearranged to shut off flow of gas to burner 23 in the event steam passesfrom I I accomplish this by locating face of bulb 16 to effect heatingof the latter, the pressure of the volatile fluid in the expansiblefluid thermostat increases. With sufficient increase in pressure of thevolatile fluid in the expansible fluid thermostat, the bottom diaphragmof the element 12 is moved downwardly such a .distance that it will actagainst pin 1|. When pin 1| is moved down a suflicient distance so thatthe tongue is free of the guide member 63, the blade 65 moves toward theright in Fig. 4. When this occurs the spring clip 66 moves to its dottedline position and the contacts of switch 5| are separated to open thecircuit forvalve 25. in the manner explained above. When the adverseoperating condition is corrected and condensate return pump 32 is againoperating to return condensate from generator chamber l9 to the boiler2| and warm condensate no longer overflows into the tube TI, thepressure of the volatile fluid in the expansible fluid thermostatbecomes reduced to permit the bottom diaphragm of element 72 to flexupwardly. Under these conditions the outer portion of blade 65 can bepulled outwardly to the position shown in solid lines in Fig. 4, so thatthe switch 5| is again closed to complete an electrical circuit for thevalve 25.

As explained above, it is also desirable to shut oil the heat supply toboiler 2| in the event steam flows from generator chamber l9 throughvent 30 into the atmosphere" This may occur, for example, whencirculation of air past evaporator I2 is not effected and there is lossof load on the latter. By locating the bulb in vent 30 the bulb becomesheated when steam flows through the vent into the atmosphere. Withheating of bulb 15 the pressure of the. volatile fluid in the expansiblefluid thermostat increases to cause the bottom resilient diaphragm ofelement 12 to move downwardly to act on pin 1|, whereby switch 5| isopened to break the electrical circuit for the valve 25, in the mannerexplained above when bulb I6 becomes heated. When the adverse operatingcondition is corrected and steam no longer flows through vent 30, thepressure of the volatile fluid in the expansible fluid thermostatdecreases so that the bottom diaphragm of the element 12 will moveupwardly to the position shown in Fig. 4. When this occurs the outerpart of blade 65 can be pulled outward to the position shown in Fig. 4,so that the contacts of switch 5| are again closed to complete thecircuit for valve 25.

The thermostatic control 50 is. so constructed and arranged that the blde or arm 65 must be manually reset to close switch 5| after an adverseoperating condition has been corrected. When the blade 65 is at theextreme righthand position shown in Fig. 5, the port on I8 outside ofcasing 54 may be painted any suitable color, .such as red, and theportion 19 inside the casing may be painted another color. such asblack, for example. During normal operation when the blade 65 is in itsoutermost position, as shown in solid lines in Fig. 4. both the red andblack portions 18 and 19 are visible so that it will immediately beapparent that switch 5| is closed and no adverse operating condition hasoccurred to cause shutting off the heat supply to boiler 2|. However, ifthe element 12 of the expansible fluid thermostat has acted on pin 1| tocause blade 65 to move into casing 54 to cause switch 5| to open, onlythe red portion 18 of the blade is visible so that it will immediatelybe apparent that an adverse operating condition has occurred to shut oilthe heat supply tothe boiler 2|. Thus,

' the control described above will open the circuit even though switch5| is of the micro-switch type operable when only a movement ofapproximately .001 inch is imparted to pin or plunger 53, the blade orarm. 55 serves as a part having a relatively large movement to showimmediately upon visual inspection whether or not switch -5| is closedor open depending uopn the position of blade 65.

In addition to the control described, a normal control is usuallyprovided for the fuel supply to the burner 23 or a plurality of suchburners, so that the rate at which steam is supplied to generator steamchamber I9 can 7 are also connected in the circuit of the valve 25 sothat, when an adverse operating condition oc-- curs which causes flow ofsteam through the vent 30 or overflow of warm condensate into tube 11,

of the solenoid valve to shut off flow of fuel to the burner or burners.When the adverse operating condition is corrected and steam no longerflows through the vent '30 or warm condensate does not overflow intotube 11, the switch 5| can be manually closed to complete the circuitfol the valve 25 so that the above-described normal control of theburner 23 may be resumed to control the-rate at which heat is suppliedto boiler 2|.

Although a single embodiment of the invention has been shownanddescribed. it will be apparent that modifications and changes canreadily be made without departing from the spirit and scope of theinvention, as pointed out in the following claims.

' What is claimed is:

1. In refrigeration apparatus, a micro-switch provided with an operatingpin having a .reciprocatory movement, said switch being operable withmovement imparted to said pin in the neighborhood of .001 inch, anexpansible fluid thermostat responsive to a temperature conditionaifected by said apparatus and including a hollow element having amovable wall member, mechanism operatively associating said pin and saidwall member, said mechanism including a blade having reciprocatorymovement in a lengthwise direction through a distance considerablygreater than .001 inch and serving as an indicator to indicate thecondition of said switch, said blade also being movable in a seconddirection transverse to its length, and said mecha nism being soconstructedand arranged that said blade is manually movable in alengthwise direction to a first position and biased to move to anotherposition when movement is imparted thereto in the second directionbysaid movable wall member, the movement of said blade to said otherposition imparting movement to said pin to actuate said micro-switch.

2. In refrigeration apparatus, acontrol device including: an electricswitch, structure including a member and a thermostatic elementresponsive to a temperature condition affected by said apparatus foroperating said switch, said member having reciprocatory movement andalso being movable transverse to the direction of said. reciprocatorymovement, and said structure controllingbeing so constructed andarranged that said member is manually movable in said direction to afirst position and biased to move to another position when saidtransverse movement is imparted thereto by said thermostatic element,the movement of said member in said direction to said other positionactuating said switch, said member being of such size and havingsuflicient movement in said direction to indicate readily the conditionof said switch.

3. In refrigeration apparatus, a control device including: a switch,structure including a blade and a thermostatic element responsive to acondition aiiected by said apparatus for operating said switch, saidblade having lengthwise reciprocatory movement between first andsecond'positions and also having movement transverse to the direction ofsaid reciprocatory movement, said blade being of such size and havingsufficient lengthwise movement to indicate readily the condition of saidswitch, resilient means to urge said blade to said first position, acatch for holding said blade in said second position against the actionof said resilient means, and said structure being so constructed andarranged that said transverse movement is imparted to said blade by saidthermostatic element to release said blade from said catch to allow saidblade to move from said first position to said second position, themovement of said blade to said second position actuating said switch.

4. In apparatusoperatcd by heat and having a part provided with a.chamber; a steam boiler,

said chamber being connected to receive steam from said boiler, meansincluding a pum to return to said boiler condensate formed in saidchamber due to condensation of steam supplied thereto, structureincluding valve means, and a device responsive to a temperaturecondition afiected by warm condensate when said pump fails to operatefor operating said valve means. said device including: an electricswitch associated with said valve means, structure including athermostatic element for operating said switch, and a partmanuallymovable to a first position and serving as an indicator forindicating the position of ing biased to move from said first positionto a second position when said switch is actuated by said thermostaticelement.'

5. In a refrigeration system operated by heat and having a heatreceiving part provided with a chamber, said chamber being connected toreceive steam from a source of supply and hav ing a vent to atmosphere;structure including an electric circuit, electro-magnetically operatedvalve means in said circuit, and a device responsive to a temperaturecondition affected by flow of steam through said vent into theatmosphere for operating said valve means, said device including amicro-switch adapted to be connected in said circuit, a thermostaticelement, and mechanism operatively associating said element and saidswitch, said switch being operable with slight movement impartedthereto, and said said switch, said part bemechanism including a partmovable through a distance considerably greater than that necessary tooperate said switch, said part serving as an indicator to indicate thecondition of said switch.

6. In refrigeration apparatus having a heat receiving part, a steamboiler, said part bing arranged to receive steam from said boiler, and

means including a pump to return to said boiler icondensate formed atsaid part due to condensation of steam supplied thereto; structureincluding an electric circuit, electro-magnetically operated valve meansin said circuit, and a device for operating said valve means responsiveto a temperature condition affected by warm condensate when said pumpfails to operate, said device including a micro-switch adapted to be'a'part provided with a chamber, said chamber.

being connected to receive steam supplied thereto from a source ofsupply; a vent for venting excess steam from said chamber to theatmosphere, structure including valve means, and a device operativeresponsive to change ina temperature condition aiiected by flow of steamfrom said vent into the atmosphere for operating said valve means; saiddevice including an electric switch associated with said valve means,structure including a thermostatic element for operating said switch,and a part movable to a first position and serving as an indi cator forindicating the condition of said switch.-

said part being biased to move from said first position to a secondposition when said switch is actuated by said thermostatic element.

8. In apparatus of the character described, a'

control device including: a casing, a microswitch 'carried by saidcasing, structure comprising a thermostatic element having a movablepart disposed within said casing and an indicator operatively associatedwith said structure and having a part projecting outside said casin forindicating the condition of said switch, said indicator havingreciprocatory movement be-' tween two positions and also being movabletransverse. to the direction of said reciprocatory movement, saidstructure being so constructed and arranged that said indicator is heldin one of said positions and released from said one position and movedto the second of said positions when moved transverse to said directionby said movable part, said indicator being arranged to actuate saidswitch when moved from said first to said second position.

SVEN W! E. ANDERSSON.

